Optical mixing in epitaxial lift-off pseudomorphic HEMTs

We present optical mixing in epitaxial lift-off (ELO) pseudomorphic HEMTs (PHEMTs) at difference frequencies in the microwave regime up to 22 GHz. The 3 μm gate length AlGaAs-InGaAs PHEMT's mere lifted off their host GaAs substrates and subsequently attached to quartz slides. It was observed that the ELO devices consistently resulted in stronger signals (/spl sim/7 dB) than the non-ELO devices under frontside and backside illumination. This is attributed to improved optical coupling efficiency, a decrease in substrate leakage, and an illumination-induced back gating effect for the ELO films.